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• Today, 08:28 AM
Find the eigenvalues of the matrix, in terms of "a". The system is "stable" if all eigenvalues are negative, "unstable" if any are positive.
1 replies | 275 view(s)
• Today, 08:26 AM
The standard method would be to introduce the new variable, u= \frac{dy}{dx}. Then \frac{d^2y}{dx^2}= \frac{du}{dx}= 2x^3+ x. Now you have the...
4 replies | 417 view(s)
• 12-08-2018, 10:30 AM
This is meaningless until you specify a probability distribution.
13 replies | 592 view(s)
• 11-26-2018, 08:25 AM
At a "max" or "min" or "inflection point" of a polynomial the first derivative must be 0. At an inflection point the second derivative is also 0. ...
7 replies | 236 view(s)
• 11-26-2018, 07:57 AM
The set, W, as you show it is not a subspace. You must mean the subspace spanned by the matrices \begin{bmatrix}-5 & 0 \\ 0 & -3 \end{bmatrix} and...
3 replies | 165 view(s)
• 11-26-2018, 07:45 AM
What you have is correct. Simplifying a little, think of it as Ax+ Bx= C (A= (W)*(Q)*(D)*(F)*(C), B= (W)*(1-Q)*(P)*(D)*(F)*(C), and c= Output). We...
3 replies | 157 view(s)
• 11-23-2018, 08:04 AM
Since x^2+ y= 7, y= 7- x^2. Then y^2+ x= (7- x^2)^2+ x= x^4- 14x^2+ 49+ x= x^4- 14x^2+ x+ 49= 11. x^4- 14x^2+ x+ 38= 0. Solve that "quartic"...
3 replies | 405 view(s)
• 11-22-2018, 09:09 AM
The outer integral, with constant limits, 0 and 1, is with respect to x so mark x= 0 and x= 1 on the x-axis of an xy coordinate system. For each x...
2 replies | 272 view(s)
• 11-22-2018, 08:33 AM
These are not true. y= 6 only for x= 1 not for any other x. Since you have replaced y with 6 you must replace x with 1. Similarly y= 0 only for x=...
6 replies | 535 view(s)
• 11-13-2018, 08:11 AM
You could, at the very least, have put "/" to indicate fractions and derivatives: \left(1/r\right)\partial u/\partial r+ \partial^2 u/\partial^2r+...
1 replies | 329 view(s)
• 11-12-2018, 09:23 AM
11x- 68k= 6 Euclidean algorithm: 11 divides into 68 6 times with remainder 2: 1(68)- 6(11)= 2. 2 divides into 11 5 times with remainder 1:...
2 replies | 591 view(s)
• 11-11-2018, 06:50 PM
Your differential equation is \frac{d^2y}{dx^2}- x- 2x^3= 0 and you are asked to "sketch the paths in the xy-plane"? I would just write the...
4 replies | 417 view(s)
• 11-11-2018, 06:42 PM
If each die has 100 sides, and all 100 are equally likely, the probability that a specific die comes up 1-15 is 15/100= 3/20. The probability a...
4 replies | 355 view(s)
• 11-09-2018, 08:38 PM
a dice is biased so that i lands on 1 one quarter of the time. So P(1)= 0.25 So P(3)= 2P(2)= 3P(4) So P(5)= 1.1P(4)= .9P(6). Those must...
5 replies | 409 view(s)
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